The present invention relates to a storage apparatus and a logical volume migration method, and, for instance, can be suitably applied to a storage apparatus that performs power saving processing of hard disk drives.
Conventionally, with a storage apparatus storing data, there is a method for managing a plurality of hard disk drives (HDDs) in RAID (Redundant Array of Independent Disks) format. In this storage apparatus, at least one or more logical volumes (hereinafter referred to as the “logical volumes”) are formed in a physical storage area (RAID group) provided by a plurality of hard disk drives.
Meanwhile, in recent years, information society is rapidly developing, and the computerization of information is also rapidly advancing. Under these circumstances, the importance of storage apparatuses that store electronic information goods is increasing, and the capacity of such storage apparatuses is ever increasing. On the other hand, however, the operation costs of storage apparatuses are becoming a problem, and the current status is that needs for realizing the power saving of storage apparatuses are increasing.
Thus, proposed is a storage apparatus that seeks power saving by shutting down the hard disk drives of the RAID group when a given standby time is set to the memory in the storage apparatus, and there is no access during such standby time (for instance, refer to Japanese Patent Laid-Open Publication No. 2000-100053).
Also in recent years, there is a storage apparatus that seeks power saving by designating the hard disk drives of the RAID group to be subject to power saving, migrating data to the hard disk drives of the RAID group or another storage apparatus in which the logical volumes formed in such RAID group will not be subject to power saving, and thereafter shutting down the hard disk drives of the RAID group to be subject to power saving.
Nevertheless, in cases where an expiration date, which is a deadline for migrating a logical volume to another RAID group or another storage apparatus, is set in the logical volume, and logical volumes having the same expiration date are migrated to the same RAID group in a concentrated manner upon migration of such logical volumes, the logical volumes will be migrated as a result of the expiration date being reached around the same time.
Consequently, the hard disk drives in the RAID group will become overloaded, and there is a problem in that the data access performance from the host system to the logical volumes of the RAID group will deteriorate significantly.